Apparatus for use in sludge treatment



United States Patent [72] lnventors Klaus Theidel Bad Homburg; Wilhelm Weber, Diez (Lahn), Germany [21 Appl. No. 844,985

[22] Filed July 25, 1969 [45] Patented Dec. 22, 1970 [73] Assignee Passavant Werke Michelbacher Hutte, Germany [32] Priority July 31, 1968 [3 3] Germany [3 l 1 No. 1,784,368.4

[54] APPARATUS FOR USE IN SLUDGE TREATMENT 9 Claims, 4 Drawing Figs.

[52] US. Cl. 210/531 [51] 1nt.Cl. B0ld 21/06 [50] Field of Search 210/528,

[56] References Cited UNITED STATES PATENTS 3,398,838 8/1968 Mitchell 210/531 2,064,151 12/1936 Coulter 210/531 2,563,622 8/1951 Scott 210/531 OTHER REFERENCES Dorr-Oliver Leaflet No. 3001, 1950, pp. 1-4.

Primary Examiner-J. L. DeCesare Attorney-Larson, Taylor & Hinds ABSTRACT: Apparatus for lifting and lowering sludge scraping or removal gear in a sludge thickener basin. The gear extends in a direction away from the sludge discharge opening and the end of the gear farthest from the opening is lifted more than is the end closest to the opening. In a circular basin with a central discharge opening and with radially extending gear, the radial outermost ends of the gear are lifted a greater amount than the radial inner end thereof.

PATENTED UEB22 I970 3549.017

SHEET 1 0F 4 INVENTORS KLAUS THEIDEL WILHELM WEBER ATTORNEYS PATENTED 050221910 sum 2 or 4 20 i LP/* a P- INVENTORS KLAUS THEIDEL WILHELM WEBER ATTORNEYS PATENTEU UECZZIHYU lT SHEET 3 UF 4 INVENTORS KLAUS THEIDEL WILHELM WEBER ATTORNEYS PATENTEUUECZZIQYU 3549.017

sumuura FIG. 4

INVENTORS KLAUS THEIDEL WILHELM WEBER BY QQ/ ATTORNEYS 1 APPARATUS roR USE IN sLuucE TREATMENT BACKGRO ND OF TIIEINvENTIoN excessive. As a result thereof, the sludge will resist normal movement of the scraping and/or removal apparatus through the basin. Of course, an alternative is to use a much more powerful motor. However, on the one hand this will increase the overall cost of operation, and on the other hand the scrap-- ing and/or removal apparatus and the supporting construction therefor will then be subjected to excessively high mechanical loads. In order to avoid this difficulty, it has been known heretofore to design these scraping and/or removal apparatus to be raised and lowered in the basin. With this apparatus, when the magnitude of the sludge becomes excessive at the bottom, the apparatus is lifted to the top of the sludge. At this point the apparatus acts on theupper sludge and then gradually works-itself from the top-of the sludge down into the lower portion of the sludge, agitating the same as it gradually moves downwardly. 1

However, in all known apparatus of this type, the scraping and/or removal elementsare lifted and lo'wered as a unit ina direction generally perpendicular to the bottom of the basin,

' with the scraping 'or removal elements themselves retained in the same general orientation withrespect to each other and with respect to the bottom of the basin. That is, all of the scraping and/or removal elements are moved to the bottom of the sludge layer together or are lifted'vupwardly therefrom together. Onemajor disadvantage of'this arrangement is that when all of the elements are "lifted together, the sludge discharge opening is left completely exposed, as a result. of which this opening tends to become'obstructed, thereby hampering the overall operation of the sludge thickener basin.

Another disadvantage with known apparatus occurs. in circular sludge thickener basins. Since, in .this type of apparatus, the sludge scraping and/or removing elements normally extend radially from the center of the basin, the driving force for this type of apparatus inust always be of sufficient size to move the outer ends of the elementswhere the required driving torque'the greatest. 1

1 Thus, there exists a need for a-new'and improved scraping and/or removal apparatus for asludge thickener basin wherein the elements can be lifted without a concurrent obstruction of the sludgedischarge opening. Andthereexists a further need for improving the sludge scraping'and/or removal apparatus in a circular basin such that the requireddriving force of the scraping and/or removal elements can be reduced without a concurrent reduction in operating efficiency.

' SUMMARY or THE INVENTION and/or removal gear such that the parts of the gear farthest from the sludge discharge opening are lifted by a greater amount than the parts of said gearicloser to the said sludge discharge opening. I

With this arrangement, the distant of the gear which would require the greatest driving force' are lifted out of contact with the main part of the sludge while the full driving force is applied to the partsof the gear closest to the discharge opening. With this concentrated force applied to the said closerparts of the gear, the said closerparts will be capable of scraping and/or removing the sludge in the critical area in the vicinity of the sludge discharge opening. Thus, without utiliz ing excessive power to drive the apparatus, the apparatus is free to continue its scraping and/0r removing operation, at least in the area adjacent the said sludge discharge opening. The apparatus is used in a circular sludge thickener basin having a bottom, centrally located discharge opening. The apparatus is provided with a verticalshaft at the center of the basin. Supporting members having the scraping and/or removal elements attached thereto are then connected at their inner ends to the shaft for pivotalmovement about horizontal axes and for rotational movement with the shaft about the said vertical axis. Further means are provided for grasping the support members to pull the same upwardly about their said pivotal axes such that the outer ends of the support members are lifted upwardly by a larger amount than the innerends of the support members. These further means may comprise poles attached to the support members at points thereof radially outwardly from the said pivotal axes of the support members, these poles being slidably supported at their upper ends for rotation with the said shaft. Meansmay then be provided at the upper ends of the poles for raising and lowering the same, thereby raising and lowering the support members.

The support members may have mounted thereon any type of sludge'treatment elements such asrods, scraper blades or the like.

r In a preferred arrangement of the invention, the support members may be raised and lowered automatically. For example, they may be raised in response to a torque dependent switch which is actuated when the force exerted by the sludge on the lowered scraping and/or removal elements become excessive. The blades may then be lowered after a predetermined time delay.

Thus, it is an object of this invention to provide a new and improved apparatus for raising and lowering, scraping and/or removal apparatus in a sludge thickener basin.

It is 'another object of this invention to provide a new and improved apparatus for raising and'lowering sludge scraping and/or removing gear wherein the .parts of the gear farthest .from the sludge discharge opening are:raised by a greater amount than the parts closer to the sludge discharge opening.

It is still another object of this invention to provide a new and improved apparatus for raising and lowering sludge scrap apparatus are raised.

' It is still another object of this invention to provide a new and improved sludge scraping and/or removal apparatus which may be operated more efficiently.

Other objects and the attendant advantages of the present invention will become apparent from the detailed description to follow, together with the accompanying drawings.

BRIEF DESCRIPTION or. THE DRAWINGS I The attached drawings are provided to illustrate a preferred embodiment of the invention.

FIG; 1 is an elevational view of a sludge thickener basin including an apparatus constructed in accordance with the features of the present invention.

FIG. 2 is a partial plan view taken'along line 2-2 of FIG. 1

i with some of the elements above line 2-2shown in dotted lines.

FIG. 3 is an enlarged shown in FIG. 1.

FIG. 4 is a plan view of the elements shown in FIG. 3.

DETAILED DESCRIPTION or THE PREFERRED EMBODIMENT Referring now to the drawings, like elements are view of a portion of the apparatus represented by like numerals throughout the several views.

Referring to FIGS. 1 and 2, and especially FIG. I, there is shown a sludge thickener basin 1 having a lid 2 covering the top of the basin. A railing 3 extends about the circumference at the top of the basin and an access opening such as a manhole 4 is provided for access into the sludge thickener basin 1. A superstructure 5, the details of which will be explained in greater detail below, is mounted on the lid 2.

The sludge thickener basin shown in these views is a circular basin having a conical floor 11 which extends downwardly to a sludge hopper 12 which in turn leads to the sludge outlet 13. At the top of the basin there is provided suitable vent openings 14 and a sludge inlet pipe 15. A hollow shaft 23 extends vertically at the center of the basin. This shaft includes openings 24 and a deflector 25 for directing the sludge entering through inlet 15 through the outer wall of the shaft 23 and outwardly to the floor of the basin.

The sludge scraping and/or removing apparatus is mounted on this shaft for rotation therewith The apparatus on the lefthand side (FIG. 1) is described with the numerals 19 through 22 and 26 through 32. The apparatus on the right-hand side (FIG. 1) is identical and is referred to by corresponding numerals 19' through 22' and 26' through 32. Further, while the preferred embodiment includes two such apparatus, it will be apparent that the invention may include only a single apparatus or more than two such apparatus. 1

Referring now to FIGS. 1 and 2, this sludge scraping and/or removing apparatus includes a support arm 20 onto which are formed suitable means for acting upon the sludge in the basin. In this embodiment the support arms 20 are provided with vertically extending scraper rods 21 and scraper blades 22, these blades being attached to the support arms 20 by suitable connecting members 19. The support arm 20 is connected to the shaft 23 for pivotal movement about horizontal axis 26 and for movement with the shaft 23 about its vertical axis.

For raising and lowering the support arm 20 and its connected elements, there is provided a pole 27 pivotally connected to the support arm 20 at pivot connection 28. The upper end 29 of this pole 27 is threaded and is slidably supported in bracket 30 and is threadedly engaged in a nut 31. A small electric motor 32, also connected to the bracket 30, is provided for turning the nut 31, thereby raising and lowering the threaded portion 29, and hence also the entire pole 27 and also the support arm 20 and its associated elements about pivot axis 26.

There is also provided a special scraping blade 33 located directly in the discharge hopper 12 and connected by a rod 34 to the shaft 23 for rotational movement therewith.

A platform 40 is mounted on the superstructure and this includes both the means for turning the shaft 23 and also the means for automatically raising and lowering the scraping and/or removing apparatus. Referring to FIG. 3, the platform 40 has mounted thereon a motor 41 with a downwardly extending output shaft 45 to which is connected a pinion gear 44. This in turn engages a ring-type drive gear 42 which is connected by a plate 42' directly to the shaft 23 and which is positioned by ball bearings 43. Thus, rotation of the shaft 45 causes rotational movement of the shaft 23. While FIG. 3 shows the elements on only one side of the vertical axis through shaft 23, it will be apparent that the elements 42, 42' and 43 are circular, and hence appear identical on the opposite side of the axis through shaft 23. Also, the position of motor 41 in relationship to the overall apparatus is visible, in addition to FIG. 3, in FIG. 1 and in dotted lines in FIG. 2.

In the operation of the apparatus, it is preferred that the raising and lowering of the scraping and/or removing apparatus be carried out automatically. Preferably, the raising of the apparatus will be responsive to an increase in the resistive force offered by the accumulating sludge counteracting the force intended to turn the shaft 23, and the lowering of the apparatus would preferably take place after a predetermined time delay following the raising of the apparatus. For this purpose, and referring in particular to FIGS. 3 and 4, the motor 41 is mounted on roller bearings 46 to permit rotational movement of the same and the casing of the motor is held by a bracket 47 which engages a bolt connected to a member 56.

This member 56 extends from its connection with bracket 47 through a block 55 to a lefthand end which is visible in FIGS. 3 and 4. This block 55 is fixed with respect to a plate 51 which is in turn fixed with respect to the platform by means of a pin 52'which engages a bracket rigidly connected to the platform 40. This bracket 50 is also visible in FIGS. 2 (in dotted lines) and FIG. 3. Vertical sidewalls 53 and 54 extend upwardly from the bottom of plate 51. Between its ends, and in the mounting block 55, the element 56 is urged to the left (FIG. 4) by suitable cup springs 58 which are visible in FIG. 3. Also connected to the element 56 is an arm 57 which threadingly engages a bolt 64 onto which is threadingly engaged a wedge member 65. A switching element 59 is mounted above the block 55. This element is switched by means of a button 62 which is operated when the lever element 60 is pivoted clockwise (FIG. 4) about its pivot axis. This in turn is accomplished by movement to the right of the wedge 65, whereupon the wedge engages the roller element 61 rotatably mounted on the lever 60. In practice, when the scraping and/or removing apparatus is subjected to excessive resistance, the motor 41 will tend to turn clockwise (FIG. 4) about its axis, thereby urging elements 56, 57, 64 and 65 to the right (FIG. 4) whereupon the roller 61 is moved to operate the switch 59. This in turn operates the small electric motors 32 and 32 to turn the threaded nuts 31 and 31 for raising the support arms 20 and 20' and their associated scraping and/or removing elements. After a suitable delay, the motors 32 and 32' may then be turned in the opposite direction to lower the scraping and/or removing apparatus. This lowering should be gradual so that the scraping and/or removing apparatus first scrapes the uppermost accumulation of sludge and then gradually the lowermost accumulation of sludge.

The invention operates as follows. During normal operation the shaft 23 is rotated with the support arms 20 and 20 in their lowermost positions so that scraping blades 22 and 22 move along the bottom of the tank. Meanwhile the scraper blade 33 continuously moves in the discharge hopper 12. During normal operation, the blades will move the sludge into the hopper 12 and through the outlet 13. Upon an excessive accumulation of sludge in the tanks, however, movement of each arm 22 and its associated elements will be resisted. This increased resistance will immediately increase the required torque at motor 41 and this in turn will move the bracket 47 and also the element 56 and the element 65 to the right (FIG. 4) thereby operating the switch 59 causing operation of motors 32 and 32' for raising the poles 27 and 27 and hence for raising the arms 20 and 20 about their respective axes 26 and 26'. In this condition, the outermost scraping blades and scraping rods which require the greatest torque to drive, are lifted out of contact with the solids while the full driving force is applied to the innermost blades 22 and 22'. Since the entire driving force is concentrated on these innermost scraping and removing elements, the force will be sufficient to continue rotating the shaft 23 whereby the innermost scraping blades and scraping rods continue to clear the sludge in the center of the basin adjacent the discharge hopper 12. After a suitable time delay required for clearing at the central area of the basin, a further switch (not shown) turns the motors 32 in the opposite direction to gradually lower the poles 27 and 27. This causes the sludge to be scraped gradually from top to bottom and conveyed to the sludge discharge hopper 12.

Although the invention has been described in considerable detail with respect to a preferred embodiment, it will be apparent that the invention is capable of numerous modifications and variations apparent to those skilled in the art.

We claim:

1. A sewage treatment apparatus comprising a circular sludge basin, a central sludge outlet hopper located at the floor of the basin in the center thereof, said hopper communicating with a sludge outlet opening, the floor of said basin being generally conical, sloping downwardly towards the said central sludge outlet hopper, a shaft supported by means located above the floor of the basin, said shaft positioned vertically in the basin on the central axis thereof above the said outlet such that the bottom center of the basin is free from shaft support means and such that the upper edge of the outlet hopper intersects the floor of the basin about its entire periphery, at least one support member connected to the shaft to travel about the said central axis as the shaft rotates, said support member extending radially outwardly from the shaft, sludge engaging elements mounted on the support member and extending downwardly therefrom toward the floor of the basin and arranged to scrape sludge along the floor of the basin and into the central outlet hopper as the support member travels around the basin, lifting means for raising and lowering the support members and its associated sludge engaging elements, said lifting means including means for raising those parts of the support member and the sludge engaging elements farthest from the sludge outlet hopper a greater distance than it raises the parts of the support member and the sludge engaging element closest to the central sludge outlet hopper, at least the outer portion of said shaft terminating a sufficient distance above said outlet hopper such that the said closest sludge engaging element can project beyond the periphery of the hopper, and wherein the said closest sludge engaging element extends a substantial distance radially inwardly beyond the periphery of the outlet hopper toward said central axis to urge sludge directly into this hopper at any position about the central axis of the basin and in both the lowered and at least the partially raised positions of the support member.

2. Apparatus according to claim 1, wherein the innermost end of the support member is connected to the shaft for pivotal movement about a horizontal axis, and wherein said lifting means includes means for turning the support member about said pivot axis whereby the radial outermost end of the support member is lifted more than theradial inner end.

3. Apparatus according to claim 2 including a pole connected to the support member and extending upwardly therefrom, whereby by pulling the pole up, the support member, together with its connected sludge engaging elements, is raised by being turned about the said horizontal axis at its pivot connection with the shaft.

4. Apparatus according to claim 3, wherein said pole is slidably attached to said shaft for rotation therewith.

5. Apparatus according to claim 4, wherein an upper part of the pole includes screw threads, and including a nut engaging said screw threads, and including motor means for turning the nut to raise and lower the said pole.

6. Apparatus according to claim 1, wherein said support member has mounted thereon both scraping rods and scraping blades, and wherein said rods and blades normally extend farther below the support member closer to the center of the basin than towards the radial outer part thereof, whereby, in the lowered position of the support member, all said rods are located approximately the same vertical distance from the floor of the basin and all of said blades are also located approximately the same vertical distance from the floor of the basin.

7. Apparatus according to claim 1 including control means for automatically raising and lowering said support member.

8. Apparatus according to claim 7. including a motor for turning said shaft, and wherein said control means includes a first switch operable in response to a predetermined torque on said motor to raise the support member, and a second switch operable after a predetermined time delay to lower the sup port member.

9. Apparatus according to claim 1, including a scraper blade rotatable with said shaft and positioned to scrape the walls of said hopper. 

